• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.912-917
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• 2007

Many electrochemical power devices such as solid state batteries and solid oxide fuel cell have been studied and developed for solving energy and environmental problems. An amperometric gas sensor usually generates sensing signal of electric current along the proportion of the concentration of target gas under the condition of limiting current. For narrow variations of gas concentration, the amperometric gas sensor can show higher precision than a potentiometric gas sensor does. In additional, cross sensitivities to interfering gases can possibly be mitigated by choosing applied voltage and electrode materials properly. In order to improve the sensitivity to $NO_2$, the device was attached with Au reference electrode to form the amperometric gas sensor device with three electrodes. With the fixed bias voltage being applied between the sensing and counter electrodes, the current between the sensing and reference electrodes was measured as a sensing signal. The response to $NO_2$ gas was obviously enhanced and suppressed with a positive bias, respectively, while the reverse current occurred with a negative bias. The way to enhance the sensitivity of $NO_2$ gas sensor was thus realized. It was shown that the response to $NO_2$ gas could be enhanced sensitivity by changing the bias voltage.

• Journal of the Korean institute of surface engineering
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• v.36 no.2
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• pp.148-154
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• 2003

Short ($\tau$=40 $mutextrm{s}$) and high-voltage ($U_{sub}$=2~8 kV) negative substrate bias pulses were used to assist pulsed magnetron sputtering DLC films deposition. Space- and time-resolved probe measurements of the plasma characteristics have been performed. It was shown that in case of high-voltage substrate bias spatial non-uniformity of the magnetron discharge plasma density greatly affected DLC deposition process. By Raman spectroscopy it was found that maximum percentage of s $p^3$-bonded carbon atoms (40 ~ 50%) in the coating was attained at energy $E_{c}$ ~700 eV per deposited carbon atom. Despite rather low diamond-like phase content these coatings are characterized by good adhesion due to ion mixing promoted by high acceleration voltage. Short duration of the bias pulses is also important to prevent electric breakdowns of insulating DLC film during its growth.wth.

• Science of Emotion and Sensibility
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• v.15 no.4
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• pp.517-526
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• 2012

This study investigated the impact of individual differences in motivational reactivity on cognitive effort, memory strength (sensitivity) and decision making (criterion bias) in response to Internet ads with positive and negative content. Individual variation in trait motivational activation was measured using the Motivational Activation Measurement developed by A. Lang and her colleagues (A. Lang, Bradley, Sparks, & Lee, 2007). MAM indexes an individual's tendency to approach pleasant stimuli (ASA, Appetitive System Activation) and avoid unpleasant stimuli (DSA, Defensive System Activation). Results showed that individuals higher in ASA exert more cognitive effort during positive ads than individuals lower in ASA. Individuals higher in DSA exert more cognitive effort during negative ads compared to individuals lower in DSA. ASA did not predict recognition memory. However, individuals higher in DSA recognized ads better than those lower in DSA. The criterion bias data revealed participants higher in ASA had more conservative decision criterion, compared to participants lower in ASA. Individuals higher in DSA also showed more conservative decision criterion compared to individuals lower in DSA. The theoretical and practical implications are discussed.

• Korean Journal of Organic Agriculture
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• v.19 no.4
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• pp.565-575
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• 2011

Recently, the use of antibiotics to improve animal productivity in livestock industry was strictly restricted. For these reason, probiotics have been regarded as one of promising materials for an antibiotic alternative. In this study, we investigated how the probiotics influences on the performance of broiler chicken via meta-analysis. Eighteen researches from 1997 to 2010 were used for meta-analysis. The standard summary effects were calculated via fixed effect model and random effect model (Borenstein et al., 2009). Heterogeneity was calculated by using the Cochran's Q statistics (Kook et al., 2009) and publication bias was calculated via Egger's regression (Lee et al., 2011). In fixed model average daily gain, body weight serum protein content and cecal LAB showed positive effect significantly. Feed intake, feed/gain and serum cholesterol showed significant negative effect. In serum triglyceride, negative effect was found but significance was not shown. In random model, average daily gain body weight and cecal LAB showed positive effects with significance and feed/gain and serum cholesterol represented significant negative effects. Publication bias was found only in feed/gain.

• International journal of advanced smart convergence
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• v.9 no.2
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• pp.20-27
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• 2020

Sound event detection in real-world environments suffers from the interference of non-stationary and time-varying noise. This paper presents an adaptive noise reduction method for sound event detection based on non-negative matrix factorization (NMF). In this paper, we proposed a deep learning model that integrates Convolution Neural Network (CNN) with Non-Negative Matrix Factorization (NMF). To improve the separation quality of the NMF, it includes noise update technique that learns and adapts the characteristics of the current noise in real time. The noise update technique analyzes the sparsity and activity of the noise bias at the present time and decides the update training based on the noise candidate group obtained every frame in the previous noise reduction stage. Noise bias ranks selected as candidates for update training are updated in real time with discrimination NMF training. This NMF was applied to CNN and Hidden Markov Model(HMM) to achieve improvement for performance of sound event detection. Since CNN has a more obvious performance improvement effect, it can be widely used in sound source based CNN algorithm.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.5
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• pp.526-532
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• 2015

We quantitatively investigated instability mechanisms under simultaneous positive gate and drain bias stress (SPGDBS) in self-aligned top-gate amorphous indium-zinc-oxide thin-film transistors. After SPGDBS ($V_{GS}=13V$and $V_{DS}=13V$), the parallel shift of the transfer curve into a negative $V_{GS}$ direction and the increase of on current were observed. In order to quantitatively analyze mechanisms of the SPGDBS-induced negative shift of threshold voltage (${\Delta}V_T$), we experimentally extracted the density-of-state, and then analyzed by comparing and combining measurement data and TCAD simulation. As results, 19% and 81% of ${\Delta}V_T$ were taken to the donor-state creation and the hole trapping, respectively. This donor-state seems to be doubly ionized oxygen vacancy ($V{_O}^{2+}$). In addition, it was also confirmed that the wider channel width corresponds with more negative ${\Delta}V_T$. It means that both the donor-state creation and hole trapping can be enhanced due to the increase in self-heating as the width becomes wider. Lastly, all analyzed results were verified by reproducing transfer curves through TCAD simulation.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.450-450
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• 2012

In recent days, advances in ZnO-based oxide semiconductor materials have accelerated the development of thin-film transistors (TFTs), which are the building blocks for active matrix flat-panel displays including liquid crystal displays (LCD) and organic light-emitting diodes (OLED). In particular, the development of high-mobility ZnO-based channel materials has been proven invaluable; thus, there have been many reports of high-performance TFTs with oxide semiconductor channels such as ZnO, InZnO (IZO), ZnSnO (ZTO), and InGaZnO (IGZO). The reliability of oxide TFTs can be improved by examining more stable oxide channel materials. In the present study, we investigated the effects of an ALD-deposited water vapor permeation barrier on the stability of ZnO and HfZnO (HZO) thin film transistors. The device without the water vapor barrier films showed a large turn-on voltage shift under negative bias temperature stress. On the other hand, the suitably protected device with the lowest water vapor transmission rate showed a dramatically improved device performance. As the value of the water vapor transmission rate of the barrier films was decreased, the turn-on voltage instability reduced. The results suggest that water vapor related traps are strongly related to the instability of ZnO and HfZnO TFTs and that a proper combination of water vapor permeation barriers plays an important role in suppressing the device instability.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2014.10a
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• pp.769-772
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• 2014

The device reliability in amorphous InGaZnO under NBS(Negative Bias Stress) and hot carrier stress with different gate overlap has been characterized. Amorphous InGaZnO thin film transistor has been measured. and is channel $width=104{\mu}m$, $length=10{\mu}m$ with gate overlap $length=0,1,2,3{\mu}m$. The device reliability has been analyzed by I-V characteristics. From the experiment results, threshold voltage variation has been increased with increasing of the gate overlap length after hot carrier stress. Also, threshold voltage variation has been decreased and Hump Effect has been observed later with increasing of the gate overlap length after NBS.

• Survey Research
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• v.3 no.2
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• pp.47-76
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• 2002

Starting point bias arises in the iterative bidding framework when the initial bid influences respondent's final bids. The bidding game has become the most commonly used method of asking the valuation question in contingent valuation studies. A bidding game is typically conducted by either personal or telephone interview. Bidding begins with an interviewer positing an initial bid (starting bid) to a respondent. If the respondent is willing to pay the initial bid, the interviewer revises the bid upward until a negative respondent is obtained. A negative response to the initial bid downward until an acceptable amount is found. The final bid is a measure of the respondent's Hicksian compensating or equivalent surplus for the item being valued. This paper explicity tested for starting point bias in bidding games. That is, it was asked whether final bids are influenced by the magnitude of the starting bids in the process of valuating the WTP when to improve the quality of running water in Seoul and its vicinity. The result shows staring point bias exists in the present data and its magnitude is ${\delta}$=-0.265237.

• Journal of the Korean Vacuum Society
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• v.9 no.4
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• pp.382-388
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• 2000

Hydrogenated amorphous carbon (a-C:H) films were fabricated by electron cyclotron resonance plasma-enhanced chemical vapor deposition. The bonding structure of carbon and hydrogen in the a-C:H films has been investigated by varying the deposition conditions such as ECR power, gas composition of methane and hydrogen, deposition time, and negative DC self bias voltage. The bonding characteristics of the a-C:H thin film were analyzed using FTIR spectroscopy. The IR absorption peaks of the film were observed in the range of $2800\sim3000 \textrm{cm}^{-1}$. The atomic bonding structure of a-C:H film consisted of $sp^3$ and $sp^2$ bonding, most of which is composed of $sp^3$ bonding. The structure of the a-C:H films changed from $CH_3$ bonding to $CH_2$ or CH bonding as deposition time increased. We also found that the amount of dehydrogenation in a-C:H films was increased as the bias voltage increased.